1. Field of the Invention
The present invention relates to an electromechanical programmer with smooth program preselection.
2. Description of the Related Art
Devices such as washing machines and dishwashers usually comprise programmers which assure the sequence of operations to be executed by these devices, provided in preestablished operating programs. The programmers with smooth program preselection make it possible for the users of these washing machines or dishwashers to choose one of these operating programs in starting these devices.
The known electromechanical programmers with smooth program preselection often comprise two micromotors the first of which step by step drives--during a normal sequence of an operating program by a reducer or a speed reduction program driving a cam for allowing step passage and a passage actuating lever--a main cam unit which actuates switches or electric contacts for supplying electric current to the various electric elements of the devices on which these programmers are mounted, and the second drives this main cam unit through a reducer or a speed reduction system in a smooth preselection of a program where the switches or electric contacts associated with this main cam unit are previously turned off. The rotation of the main cam unit of these programmers without smooth preselection often requires a relatively great manual effort which can be difficult for the users. For this reason, in this programmer, the second micromotor drives this main cam unit instead of the users and the preselection of a program becomes smooth for the latter.
In some known programmers, the second micromotor is replaced by a clutch system with gears controlled by an electromagnet which is combined with the speed reduction system of the first micromotor to drive the main cam unit in a smooth preselection of a program.
Such structures prove particularly costly because they require either use of two micromotors and two reducers or speed reduction systems in the same programmer, or use of a micromotor of a speed reduction system and a clutch system with gears and with control by an electromagnet in the same programmer.